pub(crate) struct SyncWrapper<T>(T);

impl<T> SyncWrapper<T> {
	/// Creates a new SyncWrapper containing the given value.
	///
	/// # Examples
	///
	/// ```ignore
	/// use hyper::common::sync_wrapper::SyncWrapper;
	///
	/// let wrapped = SyncWrapper::new(42);
	/// ```
	pub(crate) fn new(value: T) -> Self {
		Self(value)
	}

	/// Acquires a reference to the protected value.
	///
	/// This is safe because it requires an exclusive reference to the wrapper. Therefore this method
	/// neither panics nor does it return an error. This is in contrast to [`Mutex::get_mut`] which
	/// returns an error if another thread panicked while holding the lock. It is not recommended
	/// to send an exclusive reference to a potentially damaged value to another thread for further
	/// processing.
	///
	/// [`Mutex::get_mut`]: https://doc.rust-lang.org/std/sync/struct.Mutex.html#method.get_mut
	///
	/// # Examples
	///
	/// ```ignore
	/// use hyper::common::sync_wrapper::SyncWrapper;
	///
	/// let mut wrapped = SyncWrapper::new(42);
	/// let value = wrapped.get_mut();
	/// *value = 0;
	/// assert_eq!(*wrapped.get_mut(), 0);
	/// ```
	pub(crate) fn get_mut(&mut self) -> &mut T {
		&mut self.0
	}

	/// Consumes this wrapper, returning the underlying data.
	///
	/// This is safe because it requires ownership of the wrapper, aherefore this method will neither
	/// panic nor does it return an error. This is in contrast to [`Mutex::into_inner`] which
	/// returns an error if another thread panicked while holding the lock. It is not recommended
	/// to send an exclusive reference to a potentially damaged value to another thread for further
	/// processing.
	///
	/// [`Mutex::into_inner`]: https://doc.rust-lang.org/std/sync/struct.Mutex.html#method.into_inner
	///
	/// # Examples
	///
	/// ```ignore
	/// use hyper::common::sync_wrapper::SyncWrapper;
	///
	/// let mut wrapped = SyncWrapper::new(42);
	/// assert_eq!(wrapped.into_inner(), 42);
	/// ```
	#[allow(dead_code)]
	pub(crate) fn into_inner(self) -> T {
		self.0
	}
}

// this is safe because the only operations permitted on this data structure require exclusive
// access or ownership
unsafe impl<T: Send> Sync for SyncWrapper<T> {}
